1. Field of the Invention
This invention relates to liquid crystal compositions, and more specifically, it relates to liquid crystal compositions which are adopted for manifesting a chiral smectic C (hereinafter referred to as SmC*) phase.
2. Description of the Prior Art
Most of the action modes of the conventional liquid crystal display elements have been of a field effect type utilizing a nematic liquid crystal or a chiral nematic liquid crystal. More recently, there has been proposed a liquid crystal display element of a new action mode different from the above, that is, a field effect type liquid crystal display element permitting a high speed response by employing a ferroelectric SmC* phase appeared with a ferroelectric liquid crystal DOBAMBC: ##STR1##
However, although it was essential for such a liquid crystal display element that the temperature region where the SmC* phase is manifested be the use temperature range for the liquid crystal display element and also that it be stable, said ferroelectric liquid crystal DOBAMBC had such high temperature region for the SmC* phase as about 70.degree.-95.degree. C. and further this was relatively unstable, and therefore its industrialization seemed difficult.
An object of this invention is to eliminate the drawback of the conventional technique and provide liquid crystal compositions having a lowered temperature region for the SmC* phase, chemically stable and suitable for use in field effect type liquid crystal display elements etc.